Pivoting Pipe Coupling Having A Movable Gripping Body

ABSTRACT

A coupling for securing pipe elements together in end-to-end relation has segments joined at one end by a pivot attachment and at an opposite end by an adjustable connection member. The segments surround a central space which receives the pipe elements. A gripping body is captured between the segments. The segments have angularly oriented reaction surfaces. The gripping body has angularly oriented contact surfaces which interface with the reaction surfaces. When the segments are drawn toward each other by the connection members, interaction between the reaction surfaces and the contact surfaces forces the gripping body radially inwardly. Inwardly facing arcuate surfaces on the segments and the gripping body engage and retain the pipe elements. A method of inserting pipe elements into the coupling while the segments and the gripping body are supported on a seal is also disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of and claims priority to U.S.application Ser. No. 13/438,186, filed Apr. 3, 2012, which is based uponand claims priority to U.S. Provisional Application No. 61/471,713,filed Apr. 5, 2011 and which are hereby incorporated by reference hereinin its entirety.

FIELD OF INVENTION

This invention relates to couplings for joining pipe elements inend-to-end relationship.

BACKGROUND

Mechanical couplings for joining pipe elements end-to-end findwidespread use throughout a broad spectrum of industries such as thechemical industry, the petroleum industry and mining, as well as inmunicipal water service and fire suppression systems for buildings andother structures.

An example of a prior art coupling currently in use is provided in U.S.Pat. No. 7,086,131, which discloses a coupling having a pair of couplingsegments joined end-to-end by fasteners received in lugs at each end ofthe segments. A sealing member is positioned between the segments. Thecoupling is pre-assembled at the factory. The segments are designed andsized to receive pipe elements in the field which are inserted directlybetween the coupling segments in the pre-assembled state, without theneed to disassemble and reassemble the coupling. After insertion of thepipe elements, the fasteners are tightened to effect a fluid-tight,mechanically restrained joint between the pipe elements.

While it is advantageous to pre-assemble such couplings because it savestime and thereby cost during construction, power tools are often used totighten the fasteners for convenience, as they are faster and lessfatiguing. Power tools are of limited value, however, where no source ofelectrical power or compressed air is available, even those tools whichare battery operated. Furthermore, power tools which cause electricalsparking may not be used in environments, such as mines, where explosiveconditions may exist. It would be advantageous to provide a pipecoupling which can be pre-assembled (and thereby secure the costadvantages and convenience of such couplings) while being easilymanually tightened by workmen installing the couplings. It is furtheradvantageous to decrease the stiffness of the joint formed by thecoupling for certain applications. This can be accomplished by employingcouplings according to the invention.

SUMMARY

The invention concerns pipe couplings for securing end portions of apair of pipe elements together end-to-end. In one example embodiment,the coupling comprises a pair of segments connected end-to-endsurrounding a central space for receiving the pipe elements. Each thesegment has a pair of arcuate surfaces positioned in spaced relation.The arcuate surfaces face the central space and are engageable with thepipe elements. A pivot attachment is positioned at one end of thesegments. The pivot attachment pivotally connects the segments to oneanother. Connection members are positioned on each of the segments at anend opposite to the pivot attachment. The connection members areadjustably tightenable for drawing the segments toward one another. Atleast one reaction surface is positioned on each of the segments. Thereaction surfaces face toward the central space. At least one grippingbody is positioned between the segments. The gripping body has a pair ofgripping surfaces positioned in spaced apart relation and facing thecentral space. A pair of contact surfaces are positioned on the grippingbody. Each of the contact surfaces are in facing relation with one ofthe reaction surfaces. Adjustable tightening of the connection memberspivots the segments about the pivot attachment thereby drawing thecoupling segments together for engagement of the arcuate surfaces withthe pipe elements. The contact surfaces interact with the reactionsurfaces to move the gripping body toward the central space forengagement of the gripping surfaces with the pipe elements.

In one example embodiment, the at least one gripping body is positionedadjacent to the connection members. In another example embodiment, theat least one gripping body is positioned adjacent to the pivotattachment.

In a particular example embodiment, each of the connection members maycomprise a projection extending outwardly from the end of the segmentopposite to the pivot attachment. The projections are adapted to receivea fastener for adjustably connecting the segments to one another. Thereaction surfaces may be positioned on each of the projections.

In some example embodiments, either or both the contact surfaces and/orthe reaction surfaces may have a convex shape.

In a particular example embodiment, the pivot attachment comprises ahinge having at least one bearing positioned on each segment, thebearings being connected by an axle. In another example embodiment, thepivot attachment comprises a hinge having a pair of bearings positionedon one of the segments and a single bearing positioned on another of thesegments. The pair of bearings is connected to the single bearing by anaxle. In another example embodiment the pivot attachment comprises atang projecting from one of the segments and a stirrup extending fromthe other of the segments. The tang interfits within the stirrup, thetang and stirrup being pivotable relatively to one another. In anotherexample embodiment the pivot attachment comprises a first projectionextending from one of the segments. A first slot is positioned in thefirst projection. a first curved surface is positioned on the firstprojection. A second projection extends from another of the segments. Asecond slot is positioned in the second projection. A second curvedsurface is positioned on the second projection. The second curvedsurface interfaces with the first curved surface. A fastener extendsthrough the first and second slots between the first and secondprojections. At least one rib may be positioned on the first curvedsurface. The at least one rib may be oriented substantially parallel tothe first slot. At least one recess may be positioned within the secondcurved surface. The at least one recess may be oriented substantiallyparallel to the first slot. The at least one rib is received within theat least one recess.

In another example embodiment the pivot attachment may comprise a firstprojection extending from one of the segments. A first slot ispositioned in the first projection. At least one first tooth ispositioned on the first projection. A second projection extends fromanother of the segments. A second slot is positioned in the secondprojection. At least one second tooth is positioned on the secondprojection. The second tooth interfaces with the first tooth. A fastenerextends through the first and second slots between the first and secondprojections. The coupling may further comprise a plurality of the firstand second teeth. The first and second teeth may comprise intermeshinggear teeth, or the first and second teeth comprise intermeshing splines,for example.

In another example embodiment the pivot attachment comprises a firstprojection extending from one of the segments. A first slot ispositioned in the first projection. A second projection extends fromanother of the segments. A tongue is positioned on the second projectionand interfaces within the first slot on said first projection. Afastener extends between the first and second projections, and throughthe first slot and the tongue.

In some example embodiments a sealing member is captured between thesegments and positioned between the arcuate surfaces. The sealing memberhas inwardly facing sealing surfaces engagable with the pipe elementsfor forming a fluid-tight joint between the pipe elements. The sealingmember may have an outer surface with a diameter sized so as to supportthe segments and the gripping body in spaced relation away from thecentral space sufficient to permit insertion of the pipe elements intothe central space. To facilitate insertion of the pipe elements, thecoupling may further comprise at least one notch positioned in at leastone of the arcuate surfaces. The notch maybe positioned adjacent to thepivot attachment.

The invention also encompasses a method of joining pipe elements in endto end relation using a coupling having opposed coupling segments and amovable gripping body positioned therebetween. In one exampleembodiment, the method comprises:

-   -   inserting the pipe elements into the coupling;    -   drawing the coupling segments into engagement with the pipe        elements by pivoting the coupling segments about a pivot axis;        and    -   moving the gripping body into engagement with the pipe elements.

The method may further comprise supporting the segments and the grippingbody on an outer surface of a seal. The segments and the gripping bodyare supported in spaced relation sufficient to permit insertion of thepipe elements into the coupling. The method may further comprisedeforming the segments so as to conform them to the pipe elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded isometric view of an example embodiment of acoupling according to the invention;

FIGS. 2 and 3 are cross-sectional views of the coupling shown in FIG. 1;

FIG. 4 is an isometric view of the coupling shown in FIG. 1;

FIG. 5 is an isometric view of an alternate embodiment of the couplingshown in FIG. 1;

FIG. 6 is an isometric view of an alternate embodiment of the couplingshown in FIG. 1;

FIG. 7 is an exploded isometric view of another example embodiment of acoupling according to the invention;

FIGS. 8 and 9 are cross sectional views of the coupling shown in FIG. 7;

FIGS. 8 a and 8 b are cross sectional views of another exampleembodiment of the coupling shown in FIG. 7;

FIG. 10 is an isometric view of the coupling shown in FIG. 7;

FIG. 11 is an isometric exploded view of another example couplingembodiment according to the invention;

FIGS. 12 and 13 are cross sectional views of the coupling shown in FIG.11;

FIG. 12A is a cross sectional view taken at line 12A-12A in FIG. 12;

FIG. 13A is a cross sectional view taken at line 13A-13A in FIG. 13;

FIG. 14 is an isometric view of the coupling shown in FIG. 11;

FIG. 15 is an isometric exploded view of another example couplingembodiment according to the invention;

FIGS. 16 and 17 are cross sectional views of the coupling shown in FIG.15;

FIGS. 18 and 19 are cross sectional views of an alternate embodiment ofan example coupling according to the invention;

FIG. 20 is an isometric view of an example pivot attachment useable witha coupling according to the invention;

FIGS. 21 and 22 are cross sectional views taken at line 21-21 of FIG.20;

FIG. 23 is an isometric view of an example pivot attachment useable witha coupling according to the invention;

FIG. 24 is a cross sectional view of an example coupling having thepivot attachment shown in FIG. 23;

FIG. 25 is a cross sectional view of the pivot attachment depicted inFIG. 23 on an enlarged scale;

FIG. 26 is an isometric view of an example pivot attachment useable witha coupling according to the invention;

FIG. 27 is a cross sectional view of an example coupling having thepivot attachment shown in FIG. 26;

FIG. 28 is a cross sectional view of the pivot attachment depicted inFIG. 26 on an enlarged scale;

FIG. 29 is an isometric view of an example embodiment of a pivotattachment used with couplings according to the invention;

FIGS. 30 and 31 are side views showing the pivot attachment depicted inFIG. 24 in closed and open configurations respectively;

FIG. 32 is an isometric view of an example embodiment of a pivotattachment used with couplings according to the invention;

FIGS. 33 and 34 are side views showing the pivot attachment depicted inFIG. 32 in closed and open configurations respectively;

FIG. 35 is an isometric view of an example embodiment of a pivotattachment used with couplings according to the invention;

FIGS. 36 and 37 are side views showing the pivot attachment depicted inFIG. 35 in closed and open configurations respectively;

FIGS. 38 and 39 are is isometric views of an example embodiment of apivot attachment used with couplings according to the invention; and

FIGS. 40 and 41 are side views showing the pivot attachment depicted inFIGS. 38 and 39 in closed and open configurations respectively.

DETAILED DESCRIPTION

FIG. 1 shows an exploded isometric view of a coupling embodiment 10according to the invention. Coupling 10 comprises a plurality ofsegments 12 and 14. Segments 12 and 14 are connectable end-to-end tosurround a central space 16. Connection of the segments at one end 11 iseffected by means of a pivot attachment 13. In this example embodiment,pivot attachment 13 is a mortise hinge comprising a pair of bearings 15mounted on segment 12 in side by side spaced apart relation, and asingle bearing 17 mounted on segment 14. Bearing 17 is sized to interfitbetween the bearing pair 15, and all three bearings receive an axle 19which defines an axis 21 about which the segments 12 and 14 pivot onpivot attachment 13. Other pivot attachment embodiments are alsofeasible.

As shown, for example, in FIGS. 20, 21 and 22, the pivot attachment 23comprises a tang 25 mounted on segment 14. The tang projects radiallyoutwardly from the segment and interfits within a stirrup 27 which ismounted on and projects from the segment 12. The tang and stirrup bearagainst one another when the segment ends opposite to them are forcedtoward each other as shown in FIGS. 20 and 21, thereby providing asecure joint between segments 12 and 14. However, because the tang andstirrup are not fixedly attached to one another, they, and the segments12 and 14, are free to pivot away from one another, thereby acting as ahinge as shown in FIG. 22.

FIG. 23 shows an example pivot attachment embodiment 29 wherein thepivot attachment components comprise projections 31 and 33, eachprojection being mounted respectively on segments 12 and 14. Theprojections are pivotally connected to each other by a fastener 35 whichis oriented transversely to the axis 37 about which the segments pivot.In this example, the fastener comprises a nut and bolt, but it couldalso be a double headed pin. Use of a nut and bolt fastener 35 allowsfor additional adjustment of the connection between the segments 12 and14 once the joint is formed. FIG. 23 shows a slot 31 a in projection 31and a slot 33 a similarly formed in projection 33. Fastener 35 isreceived in slots 31 a and 33 a within the projections 31 and 33respectively. As shown in a comparison of FIGS. 24 and 25, theprojections 31 and 33 have interfacing curved surfaces 39 and 41 whichallow the projections, and the segments attached thereto, to pivot aboutaxis 37 between an open configuration (FIG. 25) and a closedconfiguration (FIG. 24). Note that, unlike a conventional hinge, axis 37is not fixed relative to the segments, but moves laterally as thesegments pivot. To facilitate the pivoting motion, each segment 12 and14 has a recess 43 which receives the ends 45 of fastener 35 in bearingand acts as a stop to limit the relative pivoting motion between thesegments as illustrated in FIG. 25.

Another pivot attachment embodiment 47 is shown in FIGS. 26, 27 and 28,wherein projections 49 and 51 on segments 12 and 14 have angularlyoriented interfacing surfaces 53 and 55. These surfaces permit relativepivoting motion of the segments about the axis 37 as shown by acomparison of the FIGS. 27 and 28, which illustrate motion of thesegments between an open configuration (FIG. 28) and a closedconfiguration (FIG. 27). Note that, unlike a conventional hinge, axis 37is not fixed relative to the segments, but moves laterally as thesegments pivot. FIG. 26 shows a slot 49 a in projection 49. A slot 51 ais similarly formed in projection 51. Fastener 35, received within slots49 a and 51 a defined by the projections 49 and 51. Fastener 35 againholds the segments together but permits the pivoting motion.

It may be desirable to incorporate features into the interfacingsurfaces of the projection pairs 31 and 33 which prevent relativemotions between the segments which are other than pivoting motion aboutan axis. FIG. 29 shows an example pivot attachment embodiment 57 whereinthe interfacing curved surfaces 39 and 41 (not shown) have a projectingrib 59 positioned on one side of the projection 31, and a recess 61 onthe other side of the projection. When in use, as shown in FIGS. 30 and31, the segments 12 and 14 are aligned such that the projecting rib 59on one segment interfits within the recess 61 on the other segment, andvice-versa. Interaction between the ribs and the recesses preventsrelative axial motion of the segments at the pivot attachment, therebymaintaining their mutual alignment.

In another example pivot attachment 63, shown in FIGS. 32, 33 and 34,the interfacing curved surfaces 39 and 41 of the projections 31 and 33have at least one, but preferably a plurality of teeth 65 which meshwith one another during pivoting motion of the segments to preventlateral motion of the segments relatively to one another. In thisexample the teeth 65 are gear teeth. FIG. 33 depicts the segments 12 and14 in a closed configuration; FIG. 34 depicts the segments in an openconfiguration.

In yet another pivot attachment embodiment 67, shown in FIGS. 35, 36 and37, splines 69 comprise the tooth or teeth which are associated with theinterfacing surfaces 39 and 41 of the projections 31 and 33. The splines69 intermesh similarly to gear teeth to prevent lateral motion betweenthe coupling segments. FIG. 36 depicts the segments 12 and 14 in aclosed configuration; FIG. 37 depicts the segments in an openconfiguration.

As shown in FIGS. 38-41, another pivot attachment embodiment 71 has atongue 73 mounted on the projection 33 on one segment (14). Tongue 73 isreceived within the slot 31 a of the projection 31 on the other segment(12) to prevent relative axial motion between the segments. The tongue73 engages the slot 31 a to prevent lateral motion between the couplingsegments. Note that the tongue 73 may be split to accommodate thefastener 35. FIG. 40 depicts the segments 12 and 14 in a closedconfiguration; FIG. 41 depicts the segments in an open configuration.

The various pivot attachment embodiments shown in FIGS. 17-33 aredisclosed in detail in U.S. Pat. No. 4,702,499 to de Raymond et al.,which is hereby incorporated by reference herein in its entirety. It isnoted that the pivot attachment joining the segments may have a centerof motion about which the segments rotate which is fixed relatively tothe coupling. For example, traditional hinges, such as the mortise hingeshown in FIG. 1, have a fixed center of motion, indicated by axis 21.However, the invention also encompasses pivot attachments for which theinstantaneous center of motion is not fixed, but moves as the segmentspivot relatively to one another. Such pivot attachments are shown inFIGS. 23-25 herein, which show the movement of the instantaneous centerof motion by the shifting of axis 37.

With reference again to FIG. 1, connection of the segments 12 and 14 atend 75 opposite to the pivot attachment 13 is effected by a connectionmember 18. In this embodiment, the connection member comprisesprojections 20 which extend outwardly from the ends of the segments.Projections 20 have apertures 22 adapted to receive a fastener, such asbolt 24 which cooperates with nut 26. The fastener is adjustablytightenable and cooperates with the projections 20 for drawing thesegments 12 and 14 toward the central space 16 upon tightening.

Each segment has a pair of arcuate surfaces 28. Surfaces 28 arepositioned in spaced relation to one another and face the central space16. The arcuate surfaces engage and retain pipe elements 30 (see FIG. 4)when the fastener connecting projections 20 is tightened to draw thesegments toward each other. The arcuate surfaces may engagecircumferential grooves in the pipe elements, plain ended pipe elements,flared end pipe elements or pipe ends having a shoulder or a shoulderand bead. The arcuate surfaces 28 may have notches 87 positionedadjacent to the end 11 having the pivot attachment 13. Notches 87provide radial clearance which allows pipe elements to be insertedbetween the segments 12 and 14 before the segments are drawn toward thecentral space 16 to effect the joint by engaging the pipe elements 30.

Each segment also has at least one, but preferably a plurality of,reaction surfaces 32. Reaction surfaces 32 may be positioned on theconnection members 18. In the embodiment shown in FIG. 1, two reactionsurfaces 32 are positioned on each projection 20. The reaction surfacesare angularly oriented with respect to the projections, and may have anorientation angle 34 from about 30° to about 60° and are inclined so asto face the central space 16. Orientation angles of about 45° arepreferred as explained below.

Coupling 10 also comprises a gripping body 36 positioned between thesegments 12 and 14 opposite to the pivot attachment 13. The grippingbody has a pair of gripping surfaces 40 (only one being shown). Similarto the arcuate surfaces 28, the gripping surfaces are positioned inspaced apart relation and face the central space 16. The gripping bodyhas a pair of contact surfaces 42 (only one being shown) positioned infacing relation with the reaction surfaces 32 on the projections 20 ofthe segments 12 and 14. The contact surfaces are also angularly orientedwith respect to the projections, and may have an orientation angle 44from about 30° to about 60°. Orientation angles of about 45° arepreferred as explained below. Preferably, the orientation angles 34 and44 are complementary to one another, meaning that they haveapproximately the same angular orientation.

Upon assembly of the coupling 10, a seal 46 is captured within thecentral space 16 by the segments 12 and 14 and the gripping body 36.Seal 46 ensures that the coupling 10 provides a fluid-tight jointbetween pipe ends. The seal 46 is sized so that, in an undeformed state,its outer circumference 48 supports the segments 12 and 14 and thegripping body 36 in spaced apart relation sufficient for pipe elementsto be inserted into the central space 16 without disassembling thecoupling.

Operation of the coupling is described with reference to FIGS. 2-4. FIG.2 shows the coupling 10 as received from the factory in an openconfiguration in the pre-assembled state, ready for installation. Inthis configuration, the fastener 24 is not yet tightened, therebyallowing the segments 12 and 14 and the gripping body 36 to bepositioned radially outwardly away from the central space 16 to allowpipe elements (not shown for clarity) to be inserted into the centralspace. As noted above, the seal 46 is sized to hold the segments andgripping body radially outwardly to facilitate pipe insertion. Uponinsertion, the pipe elements engage the seal 46 which provides fluidtightness to the joint. Next, the bolt 24 and nut 26 are tightened,drawing the segments 12 and 14 toward one another and the central space16 and into a closed configuration as shown in FIGS. 3 and 4. As thesegments move, the arcuate surfaces 28 are brought into engagement withthe outer surface of the pipe elements to retain them in the coupling.As shown by a comparison of FIGS. 3 and 4, motion of the segments 12 and14 toward one another causes the gripping body 36 to move inwardlytoward the central space 16, in a direction substantially perpendicularto the motion of the segments. This permits the gripping surfaces 40 onthe gripping body 36 to also engage the outer surface of the pipeelements. Motion of the gripping bodies toward the central space 16 iseffected by the interaction of the contact surfaces 42 on the grippingbody with the reaction surfaces 32 on the projections 20. The angularorientation 44 and 34 (see FIG. 1) of the contact surfaces and thereaction surfaces respectively, allows the forces between the surfacesto be resolved into a component directed toward the central space. Thisforce, applied at the contact surfaces, causes the motion of thegripping body toward the central space. As noted above, orientationangles of about 45° are preferred for both the reaction surfaces and thecontact surfaces.

As shown in FIG. 2, there are multiple gaps 77 between the end faces 79of the gripping body 36, and shoulders 81 on segments 12 and 14. Thegaps 77 allow for the relative motion between the gripping body and thesegments.

It is advantageous to position the reaction surfaces 32 on theprojections 20 and have the contact surfaces 42 project substantiallyradially outwardly away from the central space 16 so that the interfacebetween the contact surfaces and the reaction surfaces is near thefastener (bolt 24, nut 26) which joins the connection members 18 (inthis example projections 20) to one another. Internal pressure withinthe coupling 10, acting on the seal 46, will force the segments 12 and14 and the gripping body 36 away from the central space. Force appliedto the gripping body within the coupling is transmitted to the segmentsat the interface between the contact surfaces 42 and the reactionsurfaces 32. Due to their angular orientation, the contact surfaces 42will tend to act like a wedge and force the projections 20 apart. Byplacing the interface close to the fastener joining the projections, theseparation of the projections will be less than if the interface werefarther from the fastener. The advantageous positioning of the contactsurface-reaction surface interface minimizes the separation of thesegments and allows the coupling to withstand higher pressures withoutleaking. Furthermore, by placing the reaction forces between thesegments and the gripping bodies near the fasteners, the distortion ofthe segments by the gripping body is lessened and the coupling bettermaintains its round shape.

FIG. 5 illustrates another example embodiment 83 of a coupling accordingto the invention. In this embodiment, the contact surfaces 42 on thegripping body 36 have a convex shape. This permits them to engage thereaction surfaces 32 tangentially when the segments 12 and 14 are drawntoward one another, resulting in reaction forces which cause motion ofthe gripping body 36 toward the central space. The reaction surfaces 32are angularly oriented. FIG. 6 shows another example coupling embodiment85, wherein the reaction surfaces 32 have a convex shape and the contactsurfaces 42 are angularly oriented. This again allows for tangentialengagement between the reaction surfaces and the contact surfaces,resulting in reaction forces which cause motion of the gripping body 36toward the central space as the segments 12 and 14 are drawn toward eachother.

FIG. 7 shows an isometric exploded view of another example couplingembodiment 50 according to the invention. Coupling 50 has segments 12and 14 joined together at one end by a pivot attachment 23, and by athreaded fastener 58 which cooperates with connection members 18 at theother end. Note that, as with the previously described couplingembodiments, any type of pivot attachment is feasible. Each segment hasarcuate surfaces 28 for engaging pipe elements. Coupling 50 has agripping body 36 positioned between the segments and opposite to thepivot attachment 23. The gripping body has four contact surfaces 52positioned on opposite sides as well as two gripping surfaces 40positioned in spaced relation and facing the central space 16. Again, inthis example, the contact surfaces are angularly oriented with respectto the connection members 18 and interface with reaction surfaces 54positioned on the connection members 18. Orientation angles 56 for thecontact surfaces from about 30° to about 60° are advantageous for thiscoupling design. It is preferred that the orientation angle of thereaction surfaces 54 be approximately the same as that of the contactsurfaces 52 as shown in FIG. 10.

As shown in FIGS. 8 a and 8 b, one or both of the contact surfaces 52and the reaction surfaces 54 may have a convex shape. Such a shape isfound advantageous when large compression forces are to be applied tothe pipe elements by the gripping body 36 and the segments 12 and 14.The convex shape of either or both the contact surfaces 52 and thereaction surfaces 54 moves the reaction point between the surfaces awayfrom the end of the surfaces and more toward the center of the grippingbody 36.

Operation of coupling 50 is similar to that of coupling 10 describedabove. As shown in FIG. 8, before tightening of fastener 58, thesegments 12 and 14 and the gripping body 36 are spaced outwardly awayfrom the central space 16 so as to allow a pipe element to be insertedinto the central space. Tightening of the fastener as shown in FIG. 9draws the segments 12 and 14 toward one another and the central space,allowing the arcuate surfaces 28 to engage the pipe elements' outersurface. Interaction between the contact surfaces 52 on the grippingbody 36 and the reaction surfaces 54 on the segments 12 and 14 forcesthe gripping body to move inwardly toward the central space as thefastener 58 is tightened. The inward motion of the gripping body allowsits gripping surfaces 40 to engage the pipe elements 30 as shown in FIG.10. Similar to the previously described coupling embodiments, a seal 46is captured between the segments 12 and 14 and the gripping body 36. Asshown in FIG. 8, the outer circumference 48 of seal 46, when undeformed,is sized to support the segments and gripping body in spaced relationaway from the central space sufficient to permit insertion of the pipeelements 30 into the central space when the coupling 50 is in an openconfiguration as shown in FIG. 8. When the coupling is in a closedconfiguration, as shown in FIG. 9, the seal 46 is compressed against thepipe elements by the segments and the gripping body and ensures a fluidtight joint.

FIG. 11 shows an exploded view of another coupling embodiment 60according to the invention. Coupling 60 comprises coupling segments 12and 14. The segments are arranged in facing relation and are joined atone end by a pivot attachment 23 and at the opposite end by connectionmembers 18. In this embodiment, as with those previously described, theconnection members comprise outwardly extending projections 20 whichreceive a fastener 58 that is adjustably tightenable. Tightening of thefastener draws the coupling segments 12 and 14 toward one another andthe central space 16.

Each segment has inwardly facing arcuate surfaces 28 positioned inspaced relation to one another. The arcuate surfaces occupy positionsbetween the ends of each segment. Reaction surfaces 32 are positioned inspaced relation at the end of each coupling segment 12 and 14 oppositeto the pivot attachment 23. The reaction surfaces 32 are positionedbetween the projections 20 and the arcuate surfaces 28 and face inwardlytoward the central space 16. The arcuate surfaces 32 extend in atangential direction around the segments. The reaction surfaces may beangularly oriented as described below.

A gripping body 36 is positioned between the segments 12 and 14 adjacentto the connection members 18. The gripping body has inwardly facinggripping surfaces 40 arranged in spaced relation. Preferably, thegripping surfaces 40 align with respective arcuate surfaces 28 when thecoupling is assembled as best shown in FIG. 14. With reference again toFIG. 11, the gripping body has contact surfaces 42 in spaced relation.Contact surfaces 42 face outwardly away from the central space 16 andengage respective reaction surfaces 32 on the segments 12 and 14. Thecontact surfaces on the gripping body cooperate with the reactionsurfaces on the segments such that, when the segments are drawn towardone another, for example, by the tightening of fastener 58, the grippingbody is urged radially inwardly as explained further below.

A seal 46 is positioned between the coupling segments 12 and 14 and thegripping body 36. Both the segments and gripping body have respectivechannels 62 and 64 (see FIG. 12). Channel 62 is positioned between thearcuate surfaces 28 and channel 64 is positioned between the grippingsurfaces 40. The channels 62 and 64 receive the seal 46. The innercircumference 66 of the seal 46 has inwardly facing sealing surfaces 68and 70 which engage pipe elements joined by the coupling to form afluid-tight seal. The seal 46 is sized so that, in an undeformed state,its outer circumference 72 supports the segments 12 and 14 and thegripping body 36 in spaced apart relation sufficient for pipe elementsto be inserted into the central space 16 when the coupling is in an openconfiguration as shown in FIG. 12. Preferably, the seal is a ring formedof an elastic, resilient material such as EPDM elastomer which deformswhen the coupling segments are drawn toward one another by adjustablytightening the connection members 18.

FIG. 12 shows the pipe coupling 60 in its pre-assembled state, in anopen configuration, ready for use. To effect a fluid-tight jointconnecting pipe elements in end-to-end relation, pipe elements 30 areinserted into the sealing member 46, so that the segments straddlefacing end portions of the pipe elements as shown in FIG. 12A. The pipeelements are inserted to an extent such that grooves 74 in the outersurfaces of the pipe elements align with the arcuate surfaces 28 of thesegments and the gripping surfaces 40 of the gripping body 36. Insertionof the pipe elements to the proper depth may be facilitated by a pipestop 76 positioned on the sealing member between the sealing surfaces 68and 70. The pipe stop projects inwardly to engage the ends of the pipeelements and limit the insertion depth as desired.

FIGS. 12 and 13 show cross-sectional views of the coupling 60 with pipeelement 30 inserted. Attention is drawn to the reaction surfaces 32 onsegments 12 and 14 engaging the contact surfaces 42 on gripping body 36.The reaction surfaces are angularly oriented so that when the fastener58 is tightened, drawing the segments 12 and 14 toward one another andinto a closed configuration as shown in FIG. 13, the gripping body 36 ismoved radially inwardly so that the gripping surfaces 40 on the grippingbody engage and grip the grooves 74 of the pipe elements 30 shown inFIG. 13A. The motion of the segments 12 and 14 toward one another alsocauses the arcuate surfaces 28 on each segment to engage and grip thegrooves as well as illustrated in FIG. 14. The pipe elements are, thus,secured in end-to-end relation. The sealing member is deformed radiallyinwardly to force the sealing surfaces 68 and 70 into further engagementwith the outer surfaces of the pipe elements. This configurationproduces a relatively rigid joint. A more flexible joint can alternatelybe provided if the motion of the arcuate surfaces is limited so thatthey do not engage and clamp the floor of the groove. To this end, thetravel of the gripping bodies is limited by the extent or length of thereaction surfaces and the contact surfaces. Limitation of motion of thearcuate surfaces on the segments toward the central space is preferablycontrolled by limiting the motion of the segments through contact of theconnection members 18.

As shown in FIG. 14, reaction surfaces 32 on segments 12 and 14 andcontact surface 42 on gripping body 36 have a common orientation angle78 measured with respect to the connection members 18, specifically, theinterface 80 between members 18. Orientation angles 78 from about 30° toabout 60° are practical, with an orientation angle of about 45° beingadvantageous for this embodiment in certain applications.

FIG. 15 shows an exploded view of another coupling embodiment 60 aaccording to the invention. Coupling 60 a comprises coupling segments 12and 14. The segments are arranged in facing relation and are joined atone end by a pivot attachment 23 and at the opposite end by connectionmembers 18. In this embodiment, as with those previously described, theconnection members comprise outwardly extending projections 20 whichreceive a fastener 58 that is adjustably tightenable. Tightening of thefastener draws the coupling segments 12 and 14 toward one another andthe central space 16.

Each segment has inwardly facing arcuate surfaces 28 positioned inspaced relation to one another. The arcuate surfaces occupy positionsbetween the ends of each segment. Reaction surfaces 32 are positioned inspaced relation at the end of each coupling segment 12 and 14 adjacentto the pivot attachment 23 (unlike embodiment 60, where the reactionsurfaces are adjacent to the connection members 18). The reactionsurfaces 32 face inwardly toward the central space 16 and extend in atangential direction around the segments. The reaction surfaces areangularly oriented as described above for embodiment 60.

A gripping body 36 is positioned between the segments 12 and 14 adjacentto the pivot attachment 23 (unlike embodiment 60 wherein the grippingbody is adjacent to the connection members 18). The gripping body hasinwardly facing gripping surfaces 40 arranged in spaced relation.Preferably, the gripping surfaces 40 align with respective arcuatesurfaces 28 when the coupling is assembled. The gripping body 36 hascontact surfaces 42 in spaced relation. Contact surfaces 42 faceoutwardly away from the central space 16 and engage respective reactionsurfaces 32 on the segments 12 and 14 as shown in FIGS. 16 and 17. Thecontact surfaces on the gripping body cooperate with the reactionsurfaces on the segments such that, when the segments are drawn towardone another, for example, by the tightening of fastener 58, the grippingbody is urged radially inwardly as explained further below.

A seal 46 is positioned between the coupling segments 12 and 14 and thegripping body 36. Both the segments and gripping body have respectivechannels 62 and 64 (see FIG. 15). Channel 62 is positioned between thearcuate surfaces 28 and channel 64 is positioned between the grippingsurfaces 40. The channels 62 and 64 receive the seal 46. The innercircumference 66 of the seal 46 has inwardly facing sealing surfaces 68and 70 which engage pipe elements joined by the coupling to form afluid-tight seal. The seal 46 is sized so that, in an undeformed state,its outer circumference 72 supports the segments 12 and 14 and thegripping body 36 in spaced apart relation sufficient for pipe elementsto be inserted into the central space 16 when the coupling is in an openconfiguration as shown in FIG. 16. Preferably, the seal is a ring formedof an elastic, resilient material such as EPDM elastomer which deformswhen the coupling segments are drawn toward one another by adjustablytightening the connection members 18.

FIG. 16 shows the pipe coupling 60 a in its pre-assembled state, in anopen configuration, ready for use. To effect a fluid-tight jointconnecting pipe elements in end-to-end relation, pipe elements 30 areinserted into the sealing member 46, so that the segments straddlefacing end portions of the pipe elements. The pipe elements are insertedto an extent such that grooves (not shown) in the outer surfaces of thepipe elements align with the arcuate surfaces 28 of the segments and thegripping surfaces 40 of the gripping body 36 (see FIG. 15). Insertion ofthe pipe elements to the proper depth may be facilitated by a pipe stop76 positioned on the sealing member between the sealing surfaces 68 and70 as shown in FIGS. 15 and 16. The pipe stop projects inwardly toengage the ends of the pipe elements and limit the insertion depth asdesired.

FIGS. 16 and 17 show cross-sectional views of the coupling 60 a withpipe element 30 inserted. Attention is drawn to the reaction surfaces 32on segments 12 and 14 engaging the contact surfaces 42 on gripping body36. The reaction surfaces are angularly oriented so that when thefastener 58 is tightened, drawing the segments 12 and 14 toward oneanother and into a closed configuration as shown in FIG. 17, thegripping body 36 is moved radially inwardly so that the grippingsurfaces 40 on the gripping body engage and grip the grooves of the pipeelements 30. The motion of the segments 12 and 14 toward one anotheralso causes the arcuate surfaces 28 on each segment to engage and gripthe grooves as well. The pipe elements are, thus, secured in end-to-endrelation. The sealing member is deformed radially inwardly to force thesealing surfaces 68 and 70 (see FIG. 15) into further engagement withthe outer surfaces of the pipe elements.

FIGS. 18 and 19 show another coupling embodiment 82, comprising segments12 and 14 joined by a pivot attachment 23 at one end and having agripping body 36 positioned between the segments opposite the pivotattachment. Coupling 82 is similar to the coupling embodimentspreviously described, but differs in that the arcuate surfaces 28positioned on the segments 12 and 14 facing the central space 16 haveradii of curvature 84 greater than the radius of curvature 86 of theouter surface 88 of the pipe elements 30 exclusive of the grooves, ifany, in the outer surfaces of the pipe elements. The relation betweenthe radii of curvature of the arcuate surfaces 28 and the pipe elements30 is illustrated in FIG. 18, which depicts the coupling 82 in an openconfiguration, ready to receive pipe elements to form a joint. FIG. 19shows the coupling 82 in a closed configuration, with pipe elements 30inserted into the central space 16 and the fastener 58 tightened,cooperating with the connection members 18 on each segment to draw thesegments toward one another, thereby engaging the arcuate surfaces withthe pipe elements and forcing the gripping body 36 toward the centralspace by interaction of contact surfaces and reaction surfaces asdescribed previously for other embodiments. Gripping surfaces 40 on thegripping body 36 move into engagement with the pipe elements, as shownby a comparison of FIGS. 18 and 19, and the segments 12 and 14 deformupon contact between their arcuate surfaces and the pipe elements suchthat the radius of curvature 84 of the arcuate surfaces 28 is reduced toconform approximately to the radius of curvature of the pipe elementsalong the line of contact 90 between them and the pipe elements, asshown in FIG. 19. The larger radius of curvature of the arcuate surfacesfacilitates insertion of the pipe elements into the coupling byproviding increased clearance when the coupling is in the openconfiguration as shown in FIG. 18. Deformable pipe couplings aredescribed in U.S. Pat. No. 7,086,131 and U.S. Pat. No. 7,712,796, bothof which are hereby incorporated by reference herein.

Couplings according to the invention realize an advantage through theuse of the moving gripping bodies which allows them to be installed fromthe pre-assembled state using hand tools. The movable gripping bodiesreduce the torque required to bring the segments together and grip thepipe elements to effect a fluid-tight joint. In addition, it is observedthat having three components engage the pipe element, i.e., the grippingsurfaces of the gripping body and the arcuate surfaces of the twosegments provide for a more rigid coupling than when more components arepresent. This increase in rigidity is believed due to manufacturingtolerances of the pipe elements and the coupling, which render itdifficult to ensure that more than three components will contact thepipe elements with the same degree of engagement.

What is claimed is:
 1. A pipe coupling for securing end portions of apair of pipe elements together end-to-end, said coupling comprising: apair of segments connected end-to-end surrounding a central space forreceiving said pipe elements, each said segment having a pair of arcuatesurfaces positioned in spaced relation, said arcuate surfaces facingsaid central space and being engagable with said pipe elements; a pivotattachment positioned at one end of said segments, said pivot attachmentpivotally connecting said segments to one another; connection memberspositioned on each of said segments at an end opposite to said pivotattachment, said connection members being adjustably tightenable fordrawing said segments toward one another; at least one reaction surfacepositioned on each of said segments, said reaction surfaces facingtoward said central space; at least one gripping body positioned betweensaid segments, said gripping body having a pair of gripping surfacespositioned in spaced apart relation and facing said central space; apair of contact surfaces positioned on said gripping body, each saidcontact surface being in facing relation with one of said reactionsurfaces, and wherein adjustable tightening of said connection memberspivots said segments about said pivot attachment thereby drawing saidcoupling segments together for engagement of said arcuate surfaces withsaid pipe elements, said contact surfaces interacting with said reactionsurfaces to move said at least one gripping body toward said centralspace for engagement of said gripping surfaces with said pipe elements.2. The pipe coupling according to claim 1, wherein said at least onegripping body is positioned adjacent to said connection members.
 3. Thepipe coupling according to claim 2, wherein each of said connectionmembers comprises a projection extending outwardly from said end of saidsegment opposite to said pivot attachment, said projections beingadapted to receive a fastener for adjustably connecting said segments toone another, said reaction surfaces being positioned on each of saidprojections.
 4. The pipe coupling according to claim 1, wherein said atleast one gripping body is positioned adjacent to said pivot attachment.5. The pipe coupling according to claim 1, wherein said pivot attachmentcomprises a hinge having at least one bearing positioned on each saidsegment, said bearings being connected by an axle.
 6. The pipe couplingaccording to claim 1, wherein said pivot attachment comprises a tangprojecting from one of said segments and a stirrup extending from theother of said segments, said tang interfitting within said stirrup, saidtang and stirrup being pivotable relatively to one another.
 7. The pipecoupling according to claim 1, wherein said pivot attachment comprises:a first projection extending from one of said segments; a first slotpositioned in said first projection; a first curved surface positionedon said first projection; a second projection extending from another ofsaid segments; a second slot positioned in said second projection; asecond curved surface positioned on said second projection andinterfacing with said first curved surface; and a fastener extendingthrough said first and second slots between said first and secondprojections.
 8. The pipe coupling according to claim 7, furthercomprising: at least one rib positioned on said first curved surface,said at least one rib being oriented substantially parallel to saidfirst slot; at least one recess positioned within said second curvedsurface, said at least one recess being oriented substantially parallelto said first slot, said at least one rib being received within said atleast one recess.
 9. The pipe coupling according to claim 1, whereinsaid pivot attachment comprises: a first projection extending from oneof said segments; a first slot positioned in said first projection; atleast a first tooth positioned on said first projection; a secondprojection extending from another of said segments; a second slotpositioned in said second projection; at least a second tooth positionedon said second projection and interfacing with said first tooth; and afastener extending through said first and second slots between saidfirst and second projections.
 10. The pipe coupling according to claim9, further comprising a plurality of said first and second teeth, saidfirst and second teeth comprising intermeshing gear teeth.
 11. The pipecoupling according to claim 9, further comprising a plurality of saidfirst and second teeth, said first and second teeth comprisingintermeshing splines.
 12. The pipe coupling according to claim 1,wherein said pivot attachment comprises: a first projection extendingfrom one of said segments; a first slot positioned in said firstprojection; a second projection extending from another of said segments;a tongue positioned on said second projection and interfacing withinsaid first slot on said first projection; and a fastener extendingbetween said first and second projections, and through said first slotand said tongue.
 13. The pipe coupling according to claim 1, whereinsaid pivot attachment comprises: a first projection extending from oneof said segments; a first slot positioned in said first projection; afirst angularly oriented surface positioned on said first projection; asecond projection extending from another of said segments; a second slotpositioned in said second projection; a second angularly orientedsurface positioned on said second projection and interfacing with saidfirst angularly oriented surface; and a fastener extending through saidfirst and second slots between said first and second projections. 14.The pipe coupling according to claim 1, further comprising a sealingmember captured between said segments and positioned between saidarcuate surfaces, said sealing member having inwardly facing sealingsurfaces engagable with said pipe elements for forming a fluid-tightjoint between said pipe elements.
 15. The pipe coupling according toclaim 14, wherein said sealing member has an outer surface sized so asto support said segments and said gripping body in spaced relation awayfrom said central space sufficient to permit insertion of said pipeelements into said central space.
 16. The pipe coupling according toclaim 1, further comprising at least one notch positioned in at leastone of said arcuate surfaces, said notch being positioned adjacent tosaid pivot attachment.
 17. The pipe coupling according to claim 1,wherein said arcuate surfaces have a radius of curvature greater thanthe radius of curvature of the outer surfaces of the pipe elements. 18.A pipe coupling for securing end portions of a pair of pipe elementstogether end-to-end, said coupling comprising: a pair of segmentsconnected end-to-end surrounding a central space for receiving said pipeelements, each said segment having a pair of arcuate surfaces positionedin spaced relation, said arcuate surfaces facing said central space andbeing engagable with said pipe elements; a pivot attachment positionedat one end of said segments, said pivot attachment pivotally connectingsaid segments to one another; connection members positioned on each ofsaid segments at an end opposite to said pivot attachment, saidconnection members being adjustably tightenable for drawing saidsegments toward one another; a pair of reaction surfaces positioned oneach of said segments, said reaction surfaces facing toward said centralspace; at least one gripping body positioned between said segments, saidgripping body having a pair of gripping surfaces positioned in spacedapart relation and facing said central space; first and second pairs ofcontact surfaces positioned on said gripping body, each said contactsurface being in facing relation with one of said reaction surfaces onsaid segments, and wherein adjustable tightening of said connectionmembers pivots said segments about said pivot attachment thereby drawingsaid coupling segments together for engagement of said arcuate surfaceswith said pipe elements, said contact surfaces interacting with saidreaction surfaces to move said at least one gripping body toward saidcentral space for engagement of said gripping surfaces with said pipeelements.
 19. The pipe coupling according to claim 18, wherein said atleast one gripping body is positioned adjacent to said connectionmembers.
 20. The pipe coupling according to claim 19, wherein each ofsaid connection members comprises a projection extending outwardly fromsaid end of said segment opposite to said pivot attachment, saidprojections being adapted to receive a fastener for adjustablyconnecting said segments to one another, said reaction surfaces beingpositioned on each of said projections.
 21. The pipe coupling accordingto claim 18, wherein said at least one gripping body is positionedadjacent to said pivot attachment.
 22. The pipe coupling according toclaim 18, wherein said pivot attachment comprises a hinge having a pairof bearings positioned on one of said segments and a single bearingpositioned on another of said segments, said pair of bearings beingconnected to said single bearing by an axle.
 23. The pipe couplingaccording to claim 18, wherein said pivot attachment comprises a tangprojecting from one of said segments and a stirrup extending from theother of said segments, said tang interfitting within said stirrup, saidtang and stirrup being pivotable relatively to one another.
 24. The pipecoupling according to claim 18, wherein said pivot attachment comprises:a first projection extending from one of said segments; a first slotpositioned in said first projection; a first curved surface positionedon said first projection; a second projection extending from another ofsaid segments; a second slot positioned in said second projection; asecond curved surface positioned on said second projection andinterfacing with said first curved surface; and a fastener extendingthrough said first and second slots between said first and secondprojections.
 25. The pipe coupling according to claim 24, furthercomprising: at least one rib positioned on said first curved surface,said at least one rib being oriented substantially parallel to saidfirst slot; at least one recess positioned within said second curvedsurface, said at least one recess being oriented substantially parallelto said first slot, said at least one rib being received within said atleast one recess.
 26. The pipe coupling according to claim 18, whereinsaid pivot attachment comprises: a first projection extending from oneof said segments; a first slot positioned in said first projection; atleast a first tooth positioned on said first projection; a secondprojection extending from another of said segments; a second slotpositioned in said second projection; at least a second tooth positionedon said second projection and interfacing with said first tooth; and afastener extending through said first and second slots between saidfirst and second projections.
 27. The pipe coupling according to claim26, further comprising a plurality of said first and second teeth, saidfirst and second teeth comprising intermeshing gear teeth.
 28. The pipecoupling according to claim 26, further comprising a plurality of saidfirst and second teeth, said first and second teeth comprisingintermeshing splines.
 29. The pipe coupling according to claim 18,wherein said pivot attachment comprises: a first projection extendingfrom one of said segments; a first slot positioned in said firstprojection; a second projection extending from another of said segments;a tongue positioned on said second projection and interfacing withinsaid first slot on said first projection; and a fastener extendingbetween said first and second projections, and through said first slotand said tongue.
 30. The pipe coupling according to claim 18, whereinsaid pivot attachment comprises: a first projection extending from oneof said segments; a first slot positioned in said first projection; afirst angularly oriented surface positioned on said first projection; asecond projection extending from another of said segments; a second slotpositioned in said second projection; a second angularly orientedsurface positioned on said second projection and interfacing with saidfirst angularly oriented surface; and a fastener extending through saidfirst and second slots between said first and second projections. 31.The pipe coupling according to claim 18, further comprising a sealingmember captured between said segments and positioned between saidarcuate surfaces, said sealing member having inwardly facing sealingsurfaces engagable with said pipe elements for forming a fluid-tightjoint between said pipe elements.
 32. The pipe coupling according toclaim 31, wherein said sealing member has an outer surface sized so asto support said segments and said gripping body in spaced relation awayfrom said central space sufficient to permit insertion of said pipeelements into said central space.
 33. The pipe coupling according toclaim 18, further comprising a respective notch positioned in each ofsaid arcuate surfaces, each of said notches being positioned adjacent tosaid pivot attachment.
 34. The pipe coupling according to claim 18,wherein said arcuate surfaces have a radius of curvature greater thanthe radius of curvature of the outer surfaces of the pipe elements. 35.A method of joining pipe elements in end to end relation using acoupling having opposed coupling segments and a movable gripping bodypositioned therebetween, said method comprising: inserting said pipeelements into said coupling; drawing said coupling segments intoengagement with said pipe elements by pivoting said coupling segmentsabout a pivot axis; moving said gripping body into engagement with saidpipe elements.
 36. The method according to claim 35, further comprisingsupporting said segments and said gripping body on an outer surface of aseal in spaced relation sufficient to permit insertion of said pipeelements into said coupling.
 37. The method according to claim 35,further comprising deforming said segments so as to conform saidsegments to said pipe elements.